This invention relates to the hollow fiber type liquid processing apparatus utilized for a hollow fiber type of artificial dialyzer, artificial lung, blood plasma separator, and the like.
Presently, many hollow fiber type liquid processing apparatus are widely used. The typical application is a hollow fiber type artificial dialyzer. The general construction of this type of artificial dialyzer is such that a bundle of many hollow fibers each made of a dialyzation membrane is housed in a cylindrical housing provided with an inlet and an outlet of dialyzation liquid, both end of the hollow fiber bundle are retained in a liquid-tight fashion by partitions made of a potting agent and secured to each end of the housing, and cap-like blood ports provided respectively with a blood inlet and a blood outlet are attached to the ends of the housing. For the dialyzation membrane, hydrophilic membranes of regenerated cellulose such as cellulose acetate and cuprammonium cellulose are used. For the potting agent, polyuretane and others are used.
The blood ports used in the existing blood dialyzers have generally a blood inlet or outlet and an annular groove. They are attached to the ends of the housing by means of threaded joints with an O-ring made of silicone rubber or a like material in the annular groove.
With such blood ports, leak of blood sometimes occurs due to incomplete insertion or dislocation of the O-ring during the fabrication process.
To solve such problems, there is proposed a hollow fiber type material transfer apparatus in U.S. Pat. No. 4,708,796. In this apparatus, as shown in FIG. 14, cap-like blood ports 50 provided with an annular elastic member 54 conjoined to the inside surface of the blood port by molding are directly attached to the housing without using fastening rings and thus solves the above problems.
However, there are following problems with this apparatus. Since the top end of the annular elastic member 54 (surface to contact with the partition) is flat and too wide, it can happen that the annular elastic member and the partition are not sealed completely liquid-tight and blood leaks between the annular elastic member and the partition or between the annular elastic member and the entrance blood port. Moreover, when first molding the annular elastic member 54 and then injection molding the blood port 50, burrs of the material used for the blood port are prone to grow at the area indicated by 58. On the other hand, when first molding the blood port 50 and then injection molding the annular elastic member 54, burrs of the material used for the annular elastic member are prone to grow at the area indicated by 56. These burrs come into contact with the circulated blood and can cause blood clots. Further, fine pieces of broken burrs can enter the blood and flow into the patient body.
Furthermore, with the conventional hollow fiber type liquid processing apparatus, the blood ports with the same inside shape are used for the entrance and exit blood ports through they are marked so by different colors. Because of this inside shape of the blood ports, there is a problem that coagulation of blood can occur while passing through the inside of dialyzer.